Leipzig is also in the Bundesliga not in La Liga and I think you are a little mistaken in this regard and for Stuttgart they just need to maintain their own position until the end of the season by continuing to win in every remaining game. And at least Stuttgart can be in that position in order to enter the Champions League competition next season, because Leipzig is still hindered by Dortmund in terms of fighting for the top four positions in the Bundesliga standings.
If Stuttgart gets to make it to the champions league competition next season which they’re are already indicating so, either RB Leipzig or Borussia Dortmund will have to forfeit their dream of playing in the champions league next season. Both of them are great teams and have been showcasing good performance that always result them in participating for the champions league every year. This year, everything turned out to be different as we are even going to see a new face lifting the Bundesliga trophy this season since it the year the league was founded. I am really loving how the league here in Germany is also getting competitive, it gives room for improvement and better performance by each team in the competition.